I like this. So much that you've made me make an edit. First time I've "pixeled" in a while... if you can call what I've done to it pixeling. Here is maybe how I would take it:

very fast brain farting.
1) I think it is too monotone, so I added the light blue (rather poorly but you get the idea), made one face-half a different color scheme than the other half, and put some green in background... which I could have incorporated elsewhere in the image if I were spending time with this.
2) I think its neat to seperate the halves of the face more. So I did.
3) Perfect dither goes against the feeling of this image. More creative color mixing would be nice.
4) Background doesn't have to have anything concrete. I put blobs of color.
Just some ideas.